HOW TO KNOW SILVER ORE.

Te Aroha News, Volume III, Issue 119, 12 September 1885, Page 7

HOW TO KNOW SILVER ORE.

[BY LA PLATA IN THB HERALD.] The question lias been repeatedly asked of late" u How is it that amongst the large number of miners and diggers we Lave on the Thames, Karangahake, Waihi und other mining fields in the Auckland province, silver has never been discovered in .pacing quantities before ?" This question has been put to me very frequently of late. ; The question is easy of solution. The Australian awl New Zealand diggers have never been acuustomed to argentiferous ores; their experience ' has ' been amongst auriferous quartz, or else alluvial gold mining. Bilver and gold mining are as different nnd 'as ! far apart from one another 1 8 tiie poles. 'There is no difficulty in identifying JauHfefons quartz ; . a tyro in the in tof prospecting can tell it ; but it is a different thing with silver ored, unless,

ns I s'iall show afterwards, the ore is what is» called native or virgin silver — that i?, actual metallic silver exa ling or cropping out of the gangue stone or matrix, be it of a granite character or of a soft tufaceous kind of stone. But these are not the only gangues in which this valuable metal is found, for it bus frequently been known in calespar, in baryties, and in pure veins of silica or qnarta, an. l in its virgin or native state has been discovered in masses, even in limestone formations. The various argentiferous ores assume so many different forms that the best ju.lge or the most experienced silver miner cannot take up a so- supposed piere of ove and affirmatively say " That is silver ore" (unless it is native or virgin silver. There is no every- day common test for this ore when not rich, therefore, the prospector when in doubt should at once take his specimen to a duly qualified metallurgist, and, moreover, to one who has every appliance and apparatus at hand, aitd nH to a common smelter, or if I may so express it — every-day melter of gold. No ; go to a thoroughly qualified man ; it will save money and also time in the long run. Silver ores occur in so many mineralised forms, which are so puzzling to non-scientific minds that it is no wonder that many a good vein has been missed and pa?sed over as worthless. Not to mention all the silver ores, we may say ( that the chlorides, chloro- bromides, j bromides, arsenides, sulphides, and \ others, each containing hi other various forms such special ores as kerargyrite or horn silver, bronwrgyrite or bromide of silver, and others too numerous to mention, are amongst those in which this valuable metal is found. Another fact worthy the attention of the silver miner and prospector is that nil the ores of this .netal of any value are soft, and where they are of a dark colour, they cut or ought to cut easily. Tm's is a criterion .is to whether they should be tested or assayed, and to this fact tie prospector when searching for silver should pay invat attention. There is also a peculiar sort of gangue stone which is frequently found in the silver mines of Nevada and Colorado, as well as Mexico, New Gr;: a !a, Bolivia, and Peiu, callel amongst American miners " mice-eaten" quartz. Tuis is a sort of honeycombed stone, with small holes and cracks in it, in which there are minute black spots. This is well known in the above countries, and when found in known silver mines indicates rich stone. I may mention that this species of quartz is frequently found in the famous Mexican silver lode, the Veta Madre, of Guanajuato, oue of the largest and richest veins ever discovered. This " miceeaten" quartz generally accompanies and is found associated with the ore called " kerargyrite." In exploring or prospecting for silver ores, there are but few recognised rules to follow, but all original mineral formations have been so changed and modified by subsequent volcanic action, that care must be taken not to confound their older (if out cropping and visible) fea- ! turea with the distorted, changed, irregular and undefined characteristics of their more modern appearances. Experience in mining shows that the richest deposits have always been worked close to or in the neighbourhood of the junction of the primitive and secondary formations. Thus primitive rocks in small hills or mounds often protrude, through clay-slates and metalliferous carbonates of lime and magnesia. It is not wise to go far away from the junction of the secondary or primitive rocks ; it is not desirable to go to the centres of well-defined mountain ranges, but to keep more to the foot-hills, as the latter are apt to be more broken, disturbed, fuller of heaves, slides, etc., and in consequence more likely to have veins and lodes traversing them. Prophyritic and granitic I hills, when in a silver district, are likely places for the prospector to explore, and when micaceous aud argillaceous slates are much upheaved, folded, tilted, and distorted, it is then in these neighbourhoods that the miner should diligently explore." I have seen lately a great deal of stone from the various mines at Karangahake and, if experience goes for anything, a bright future may well be predicted for that locality. Many of the conditions necessary in silver ruining districts are quite fulfiled in the geological formation of the surrounding country, and with the now known capability of the LaMoute process for saving nearly ail the bullion in the stone, there should be some remarkably rich mines there. I trust that these remarks which I have penned may be of use to some of our embryo silver minors, and hoping that they will be impressed by what I say in always having good and sure assays mai'e of their various mines before launching out into great expenses.